The Great Arctic Cyclone of 2016

A storm is brewing in the Arctic. A big one! The crew of the yacht Northabout are currently sailing along the western shore of the Laptev Sea and reported earlier today that:

The sea is calm. Tomorrow a gale 8. But this moment is perfect.

That perfect moment will not last long. Here is the current ECMWF forecast for midnight tomorrow:

and here is the current Arctic surf forecast for 06:00 UTC on Monday:

A 975 hPa low pressure system will be creating 3 meter waves with a period of around 8 seconds heading across the East Siberian Sea in the direction of the ice edge. By midnight on Monday the cyclone is forecast to have deepened to a central pressure below 970 hPa:

All of this is rather reminiscent of the “Great Arctic Cyclone” in the summer of 2012, which looked like this on August 7th:

and which ultimately led to the lowest Arctic sea ice extent in the satellite record. Using the National Snow and Ice Data Center’s numbers that was 3.41 million square kilometers on September 16th 2012. Here’s the NSIDC’s current graph comparing 2012 with this year:

The University of Hamburg have been processing more AMSR2 data from 2012. You can argue until the cows come home about which is the best metric to peruse at this time of year, but try this one for size:

That’s the high resolution AMSR2 sea ice area for the Arctic Basin, comprising the CAB plus Beaufort, Chukchi, East Siberian and Laptev Seas.

[Edit – August 25th]

There’s a bit of a gap in the clouds over the Central Arctic today:

NASA Worldview “true-color” image of the Central Arctic Basin on August 25th 2016, derived from the MODIS sensor on the Terra satellite

This is merely the calm before the next storm. Here is the current ECMWF forecast for Saturday lunchtime (UTC):

Low pressure on the Siberian side of the Arctic and high pressure on the Canadian side producing an impressive dipole with lots of sea ice “drift” towards the Atlantic:

[Edit – August 27th]

Saturday morning has arrived, and so has the predicted storm. As the centre of the cyclone crossed the coast of the East Siberian Sea its central pressure had fallen to 967 hPa, whilst the high pressure over Alaska had risen to 1028 hPa:

The effect of the earlier bursts of high wind is apparent in the high resolution AMSR2 sea ice area graph:

However they are not as apparent in the corresponding extent graph:

[Edit – August 28th]

As the centre of the cyclone heads for the North Pole the isobars are tightening across the last refuge of multi-year sea ice north of the Canadian Arctic Archipelago and Greenland:

The area north of the East Siberian Sea that was predicted to bear the brunt of the wind and waves overnight is still covered in cloud. However the latest AMSR2 update from the University of Hamburg suggests that open water now stretches as far as 86 degrees north:

The skies over the northern Chukchi Sea have cleared to reveal this:

NASA Worldview “true-color” image of the northern Chukchi Sea on August 28th 2016, derived from the MODIS sensor on the Aqua satellite

[Edit – August 29th]

Some of the effects of the recent high winds can be judged by this Canadian Ice Service chart of ice concentration near the North Pole:

[Edit – September 1st]

Arctic sea ice area continues to fall quickly for the time of year:

The recent dipole has finally caused some compaction of the scattered sea ice. Hence the high resolution AMSR2 extent is following suit and is now below last year’s minimum:

File this under stranger than fiction…college flunk out Anthony Watts crawled out of hiding this morning and went postal on my alter ego Saul because yours truly asked for permission to share our exchanged emails with Peter Sinclair.
In spite of, or more likely because of my numerous warnings, he has become a #GAC16 denier. I am afraid that will cost him a 42 day timeout… he is the one and only member of my twitter mute list.

Will continuing cyclonic activity impact volume measurement? Eckman pumping and wave action through open water and ice rubble should result in lower volume although I’m not sure satellite altimetry will be able to differentiate in rough sea conditions. Wider error bars for August?

At this time of the year we only have “volume modelling” rather than “volume measurement”. That will have to wait for CryoSat 2 and SMOS “thickness measurement” to restart in the Autumn.

No doubt somebody will correct me if I’m wrong, but as far as I am aware the PIOMAS model does not directly concern itself with wave/ice interaction, although it does assimilate sea ice concentration in order to try and get a better handle on thickness.

The NSIDC have published the latest edition of their Arctic Sea Ice News. The effects of waves on sea ice during the Great Arctic Cyclone are discussed at length:

It indeed appears that the August 2016 storms helped to break up the ice and spread it out, contributing to the development of several large embayments and polynyas. Some of this ice divergence likely led to fragmented ice being transported into warmer ocean waters, hastening melt. Whether warmer waters from below were mixed upwards to hasten melt remains to be determined, but as discussed below, these storms were associated with very high wave heights.

Large waves are a relatively new feature of the western Arctic Ocean. The height of waves is in part determined by surface wind speed, as well as the fetch (distance over open water that the wind can travel) and the duration of a wind event. A moderate sea ice cover damps ocean waves by absorbing and dispersing the wave energy through jostling of the ice floes against one another. A dense ice pack cover acts as a shield between the ocean and the surface wind, preventing wave formation.

In the latter half of the twentieth century, 4 to 6 meter waves (13 to 20 feet) rarely occurred in the western Arctic Ocean, but with more open water they have become more frequent, especially when strong storms enter the Arctic Ocean in late summer or early autumn. During the first of the two August cyclones discussed above, waves up to 5.9 meters (19 feet) were predicted. This occurred during the early part of the cyclone’s lifecycle (1800 UTC August 14), in the eastern Kara Sea. Further east, north of the New Siberian Islands, wave heights were estimated as high as 4.3 meters (14 feet) late on August 15. In this region, the waves were directly incident on the ice edge. In response, the ice edge retreated following the 4.3 meter waves on August 15.